unflatten

Rebuilds a nested object from a single-level object whose keys are dot-notation paths. The inverse of flatten.

Uses set internally, so intermediate nodes are always created as plain objects (never arrays — see flatten’s doc for why), and any key segment equal to __proto__, constructor, or prototype is silently rejected (same prototype-pollution guard as set).

Available since v3.0.0

Import

import { unflatten } from '@helpers4/object';
// or, from the all-in-one package (same code, one install):
import { unflatten } from 'helpers4/object';

Signature

unflatten(obj: Record<string, unknown>): Record<string, unknown>

Parameters

Parameter	Type	Description
obj	Record<string, unknown>	A single-level object with dot-notation keys

Returns

Record<string, unknown> — The rebuilt nested object

Examples

Rebuild a nested object from dotted keys

The inverse of flatten() — useful for parsing flat config sources (env vars, .ini files).

unflatten({ 'server.host': 'localhost', 'server.port': 8080 })
// => { server: { host: 'localhost', port: 8080 } }

Multiple keys under the same parent are merged

Every dotted key contributes to the same nested structure.

unflatten({ 'a.x': 1, 'a.y': 2 })
// => { a: { x: 1, y: 2 } }

Source

View source on GitHub